This study was a double-blind, placebo-controlled, cross-over, single-center study of desloratadine 5 mg or placebo in subjects 18 years of age or older with a history of seasonal allergic rhinoconjunctivitis. This study was performed to examine the effects of desloratadine compared with placebo, on the signs and symptoms of allergic conjunctivitis induced by direct conjunctival challenges with a previously identified sensitizing antigen, in the eyes of a subject known to be sensitive to the antigen.